FIG. 1 shows a cross section of a pedal stroke simulator according to the related art.
The conventional pedal stroke simulator schematically depicted in FIG. 1 is installed in the Toyota Prius III. As a housing, the conventional pedal stroke simulator includes a cast part 10 and a cover 12 inserted into cast part 10. A first hydraulic chamber 14 and a second hydraulic chamber 16 are formed in the housing. A displaceable piston 18 which bears an O-ring 20 and which is supported with the aid of two simulator springs 22 and 24 situated in second hydraulic chamber 16 is inserted between first hydraulic chamber 14 and second hydraulic chamber 16. A first simulator spring 22 of the two simulator springs 22 and 24 has a much lower spring stiffness than a second simulator spring 24 of the two simulator springs 22 and 24. Second simulator spring 24, which contacts cover 12, presses a spring plate 26 away from cover 12. Piston 18 is pressed away from the inner base surface of spring plate 26 with the aid of first simulator spring 22, which contacts an inner base surface of spring plate 26.
Brake fluid which is pressed from a master brake cylinder, connected to the conventional pedal stroke simulator, with the aid of a driver brake force is displaceable into first hydraulic chamber 14 via a connecting borehole 28 formed in cast part 10. In addition, a volume compensation opening 30 via which brake fluid is transferable from second hydraulic chamber 16 into a connected brake fluid reservoir is formed on cast part 10. Braking by a driver (via the master brake cylinder) into the conventional pedal stroke simulator initially causes a displacement motion of piston 18 from first hydraulic chamber 14 into second hydraulic chamber 16, with deformation of first simulator spring 22, until piston 18 strikes the inner base surface of spring plate 26. If the driver brakes further into the conventional pedal stroke simulator after piston 18 strikes the inner base surface of spring plate 26, piston 18 and spring plate 26 are pressed in the direction of cover 12, with deformation of second simulator spring 24. With the aid of the driver brake force, the driver may press piston 18 far enough into second hydraulic chamber 16 that an elastomer component 32 mounted on cover 12 is deformed. The aim is thus for a pressure-volume characteristic curve having a large pressure rise at the end of the volume intake to be achievable for the conventional pedal stroke simulator.